The invention relates to a radial tire, especially the formation of the unvulcanized rubber carcass ply of the tire on a tire building drum. In building a radial tire, the unvulcanized carcass ply is placed on the building drum such that the reinforcement cords of the ply extend longitudinally of the drum. The tire builder normally cuts the carcass ply, so that the opposing ends of the ply are overlapped. The overlapped ends are pressed together to form what is known as a lap joint or splice. It has been found that such joints tend to produce an unslightly waviness in the adjacent sidewalls of the finished tire. Such waviness can be eliminated or substantially reduced by using a butt splice, wherein the opposing ends of the carcass ply are in abutting relation and not overlapped.
Butt splices are old as evidenced by U.S. Pat. No. 1,043,143 which discloses the use of a fabric, conventionally woven from a soft weft thread 15 and a small warp cord 16, for covering the butt splice of a carcass ply of a bias-type tire where the reinforcement cords of the ply extend angularly across the tire building drum and not longitudinally of the drum. It appears from the drawing of the U.S. Pat. No. 1,043,143 that the warp cords of the fabric are parallel to the reinforcement cords of the bias carcass ply. The invention is directed to a unique reinforcement which reacts to maintain the butt splice intact by resisting the radial and circumferential forces that are exerted against the tire, especially during the expansion of the tire from a cylindrical to a toroidal shape.